R. J. Ardecky, A. D. Patten, and J-H Sun, U.S. Pat. No. 5,086,059, issued Feb. 4, 1992, disclose anticancer agents of formula: ##STR4##
Harnisch et al, U.S. Pat. No. 4,841,052, issued Jun. 20, 1989, disclose fluorescent quenchers of formula: ##STR5##
El-Nagger et al., Chem Abstr. 1983, 99, 88558r, disclose compounds of formula: ##STR6##
Brana et al., U.S. Pat. No. 4,874,863, issued Oct. 17, 1989, disclose anticancer agents of formula: ##STR7##
Horiguchi et al., Chem Abstr. 1972, 76, 87174a, disclose fluorescent whitening agents of formula: ##STR8##